mtd: vf610_nfc: add 32-error correction option for HW ECC

Add option to choose between current 24-error correction and 32-error
correction through Kconfig. 32-error correction allow to use NAND
chips which require up to 8-bit error correction per 512 byte (when
using 2K pages).

Signed-off-by: Stefan Agner <stefan@agner.ch>
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 0a9e96f..3024357 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -41,6 +41,21 @@
 	  The driver supports a maximum 2k page size. The driver
 	  currently does not support hardware ECC.
 
+choice
+	prompt "Hardware ECC strength"
+	depends on NAND_VF610_NFC
+	default SYS_NAND_VF610_NFC_45_ECC_BYTES
+	help
+	  Select the ECC strength used in the hardware BCH ECC block.
+
+config SYS_NAND_VF610_NFC_45_ECC_BYTES
+	bool "24-error correction (45 ECC bytes)"
+
+config SYS_NAND_VF610_NFC_60_ECC_BYTES
+	bool "32-error correction (60 ECC bytes)"
+
+endchoice
+
 comment "Generic NAND options"
 
 # Enhance depends when converting drivers to Kconfig which use this config